feat: add scroll bar to Music app

programs/src/music/main.cpp

@@ -39,6 +39,8 @@ static constexpr int FONT_SIZE_LG   = 20;
 
 static constexpr int LIST_TOP       = TOOLBAR_H;
 static constexpr int LIST_ITEM_H    = 32;
+static constexpr int LIST_SB_W      = 12;
+static constexpr int LIST_SB_MIN_TH = 20;
 static constexpr int INFO_H         = 56;
 static constexpr int PROGRESS_H     = 24;
 static constexpr int TRANSPORT_H    = 44;
@@ -144,6 +146,13 @@ struct PlayerState {
     // Progress dragging
     bool dragging_progress;
 
+    // List scrollbar
+    bool sb_dragging;
+    int  sb_drag_offset;
+    bool sb_hovered;
+    int  mouse_x;
+    int  mouse_y;
+
     // Transport icons (dark for normal, white for active/colored backgrounds)
     SvgIcon ico_rewind;
     SvgIcon ico_play;
@@ -1047,6 +1056,26 @@ static int visible_items() {
     return count > 0 ? count : 0;
 }
 
+static bool list_scrollbar_visible() {
+    return g.filtered_count > visible_items() && visible_items() > 0;
+}
+
+static void list_scrollbar_rects(int W, Rect* track, Rect* thumb) {
+    int list_h = list_bottom() - LIST_TOP;
+    int visible = visible_items();
+    int tx = W - LIST_SB_W;
+    *track = {tx, LIST_TOP, LIST_SB_W, list_h};
+
+    int max_scroll = g.filtered_count - visible;
+    if (max_scroll < 1) max_scroll = 1;
+    int th = (visible * list_h) / g.filtered_count;
+    if (th < LIST_SB_MIN_TH) th = LIST_SB_MIN_TH;
+    if (th > list_h) th = list_h;
+    int range = list_h - th;
+    int ty = LIST_TOP + (g.scroll_y * range) / max_scroll;
+    *thumb = {tx + 1, ty, LIST_SB_W - 2, th};
+}
+
 static Rect content_panel_rect() {
     int y = list_bottom() + 1;
     return {0, LIST_TOP, g.win_w, y - LIST_TOP};
@@ -1135,6 +1164,10 @@ static void render(uint32_t* pixels) {
     px_hline(pixels, W, H, 0, list_end, W, BORDER_COLOR);
 
     if (!g.show_visualizer) {
+        bool sb_vis = list_scrollbar_visible();
+        int row_w = sb_vis ? (W - LIST_SB_W) : W;
+        int tag_right = sb_vis ? (W - LIST_SB_W) : W;
+
         for (int i = 0; i < visible_count && (i + g.scroll_y) < g.filtered_count; i++) {
             int idx = filtered_raw_at(i + g.scroll_y);
             if (idx < 0) break;
@@ -1149,7 +1182,7 @@ static void render(uint32_t* pixels) {
                 bg = g_list_hover;
 
             if (bg.r != BG_COLOR.r || bg.g != BG_COLOR.g || bg.b != BG_COLOR.b)
-                px_fill(pixels, W, H, 0, iy, W, LIST_ITEM_H, bg);
+                px_fill(pixels, W, H, 0, iy, row_w, LIST_ITEM_H, bg);
 
             if (idx == g.selected_item && !(idx == g.current_track && g.play_state != PlayState::Stopped))
                 px_fill(pixels, W, H, 0, iy, 3, LIST_ITEM_H, g_accent);
@@ -1168,16 +1201,19 @@ static void render(uint32_t* pixels) {
 
             const char* tag = g.files[idx].is_mp3 ? "MP3" : "WAV";
             int tw = text_w(tag, FONT_SIZE_SM);
-            px_text(pixels, W, H, W - tw - 12, iy + (LIST_ITEM_H - fh_sm) / 2,
+            px_text(pixels, W, H, tag_right - tw - 12, iy + (LIST_ITEM_H - fh_sm) / 2,
                     tag, DIM_TEXT, FONT_SIZE_SM);
         }
 
-        if (g.filtered_count > visible_count && visible_count > 0) {
+        if (sb_vis) {
-            int list_h = list_end - LIST_TOP;
+            Rect track, thumb;
-            int sb_h = (visible_count * list_h) / g.filtered_count;
+            list_scrollbar_rects(W, &track, &thumb);
-            if (sb_h < 20) sb_h = 20;
+            px_fill(pixels, W, H, track.x, track.y, track.w, track.h,
-            int sb_y = LIST_TOP + (g.scroll_y * (list_h - sb_h)) / (g.filtered_count - visible_count);
+                    Color::from_rgb(0xF0, 0xF0, 0xF0));
-            px_fill_rounded(pixels, W, H, W - 6, sb_y, 4, sb_h, 2, TRACK_BG);
+            Color tc = (g.sb_hovered || g.sb_dragging)
+                        ? Color::from_rgb(0xA0, 0xA0, 0xA0)
+                        : Color::from_rgb(0xC0, 0xC0, 0xC0);
+            px_fill(pixels, W, H, thumb.x, thumb.y, thumb.w, thumb.h, tc);
         }
 
         if (g.filtered_count == 0) {
@@ -1620,10 +1656,64 @@ extern "C" void _start() {
 
             // Mouse
             if (ev.type == 1) {
+                g.mouse_x = ev.mouse.x;
+                g.mouse_y = ev.mouse.y;
                 bool clicked = (ev.mouse.buttons & 1) && !(ev.mouse.prev_buttons & 1);
                 bool released = !(ev.mouse.buttons & 1) && (ev.mouse.prev_buttons & 1);
+                bool held = (ev.mouse.buttons & 1) != 0;
 
-                if (clicked) {
+                // List scrollbar drag/hover
+                bool sb_consume = false;
+                if (!g.show_visualizer && list_scrollbar_visible()) {
+                    Rect sb_track, sb_thumb;
+                    list_scrollbar_rects(g.win_w, &sb_track, &sb_thumb);
+                    bool in_track = sb_track.contains(ev.mouse.x, ev.mouse.y);
+
+                    if (g.sb_dragging && held) {
+                        int list_h = sb_track.h;
+                        int range = list_h - sb_thumb.h;
+                        int max_scroll = g.filtered_count - visible_items();
+                        if (range > 0 && max_scroll > 0) {
+                            int new_ty = ev.mouse.y - g.sb_drag_offset;
+                            int rel = new_ty - LIST_TOP;
+                            if (rel < 0) rel = 0;
+                            if (rel > range) rel = range;
+                            int new_scroll = (rel * max_scroll + range / 2) / range;
+                            if (new_scroll != g.scroll_y) {
+                                g.scroll_y = new_scroll;
+                                clamp_list_scroll();
+                                redraw = true;
+                            }
+                        }
+                        sb_consume = true;
+                    } else if (g.sb_dragging && released) {
+                        g.sb_dragging = false;
+                        redraw = true;
+                        sb_consume = true;
+                    } else if (clicked && in_track) {
+                        if (sb_thumb.contains(ev.mouse.x, ev.mouse.y)) {
+                            g.sb_dragging = true;
+                            g.sb_drag_offset = ev.mouse.y - sb_thumb.y;
+                        } else {
+                            int visible = visible_items();
+                            int delta = visible > 1 ? visible - 1 : 1;
+                            if (ev.mouse.y < sb_thumb.y) g.scroll_y -= delta;
+                            else                          g.scroll_y += delta;
+                            clamp_list_scroll();
+                        }
+                        redraw = true;
+                        sb_consume = true;
+                    }
+                    if (in_track != g.sb_hovered) {
+                        g.sb_hovered = in_track;
+                        redraw = true;
+                    }
+                } else if (g.sb_hovered) {
+                    g.sb_hovered = false;
+                    redraw = true;
+                }
+
+                if (clicked && !sb_consume) {
                     if (handle_click(ev.mouse.x, ev.mouse.y))
                         redraw = true;
                 }
@@ -1645,7 +1735,9 @@ extern "C" void _start() {
 
                 // Hover tracking for file list
                 int lb = list_bottom();
-                if (!g.show_visualizer && ev.mouse.y >= LIST_TOP && ev.mouse.y < lb) {
+                int hover_right = list_scrollbar_visible() ? (g.win_w - LIST_SB_W) : g.win_w;
+                if (!g.show_visualizer && ev.mouse.y >= LIST_TOP && ev.mouse.y < lb
+                    && ev.mouse.x >= 0 && ev.mouse.x < hover_right) {
                     int new_hover = filtered_raw_at((ev.mouse.y - LIST_TOP) / LIST_ITEM_H + g.scroll_y);
                     if (new_hover != g.hovered_item) {
                         g.hovered_item = new_hover;